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Impact of Aerosols on Respiratory Health of Dairy Workers and Residents Living
Near Dairies: Discussion and Implications of Recent Research
Stephen J Reynolds, PhD, CIH, FAIHA
Director High Plains Intermountain Center for Agricultural Health
and Safety, Colorado State University, Ft. Collins, CO
Robert Hagevoort, PhD Dairy Extension Specialist, New Mexico
State University, Clovis, NM
2015 Waste to Worth ConfernceSeattle, Washington
March 31, 2015
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Occupational Exposures and Lung Disease
OverviewHealth or disease endpoints?
Populations?
Exposures?
Genetics?
Other risk factors?
Association and Causation
Epidemiology• Most convincing evidence for a causal
relation comes from reproducible
experimental demonstration of association.
• Observational studies on human populations
(ethics of experimentation)
o Retrospective (Case History), Prospective
(Cohort)
o Mathematical (statistical) models and
agreement on acceptable error
Community Studies:Evidence for Hygiene
HypothesisBraun-Fahrlander et al. Enviromental Exposure to Endotoxin and its relation to asthma in school age children. N Eng J Medicine 2002
Illi et al. Protection from childhood asthma and allergy in Alpine farm environments –the GABRIEL Advanced Studies. J Allergy Clin Immunol 2012
Community Studies:Evidence for Hygiene
HypothesisEge et al. Gene-environment interaction for childhood asthma and exposure to farming in Central Europe. J Allergy Clin Immunol 2011
Smit et al. Air pollution from livestock farms, and asthma, allergic rhinitis, and COPD among neighboring residents. Occup Environ Med 2014
Williams et al. Cow allergen (Bos d2) and
endotoxin concentrations are higher in settled dust
of homes proximate to industrial-scale dairy
operations. Nature 2014.
Endotoxin & Innate Immunity
Source: Cook et al. 2004
Lundell et al. High Proportion of CD5 B
Cells in Infants Predicts Development of
Allergic Disease. J Immunology 2014.
Occupational Studies • Reynolds. Systematic Review of Respiratory
Health Among Dairy Workers J Agromedicine2013
• Basinas. Sensitization to Common Allergens and Respiratory Symptoms in Endotoxin Exposed Workers: a Pooled Analysis JOEM 2012
• Senthilselvan Association of polymorphisms of toll-like receptor 4 with a reduced prevalence of hay fever and atopy. Ann Allergy Asthma Immunol 2008
Occupational Studies
• Smit. CD14 and Toll-like receptor Gene Polymorphisms, Country Living, and Asthma in Adults . Am J Respir Crit Med 2009
• Gao. Association of Toll-like receptor 2 gene polymorphisms with lung function in workers in swine operations . Ann Allergy Asthma Immunol 2013
Reynolds. Pulmonary Function Reductions Among
Potentially Susceptible Subgroups of Agricultural
Workers in Colorado and Nebraska JOEM 2012
Asthma
But ….
Risk Management in face of Uncertainty?
Liabilities – Community/consumers vs. workplace
Information needed
Communication and scientific literacy
Cost effective best practices that promote cow
health, productivity, worker health and community
health
RecommendationsIdentify locations and tasks that contribute to respiratory exposures
Provide baseline and annual medical exams
Engineering controls – ventilation, enclosed/ventilated cabs, feed additives, bedding materials, washing frequency
Protective equipment – N95 dust masks and respirators (when engineering is not available
Training
